Reliability of Piezocone Penetration Test Methods for Estimating the Coefficient of Consolidation of Cohesive Soils (05-0025)**
Murad Yusuf Abu-Farsakh, Louisiana State University
Munir D. Nazzal, Ohio University, Athens

This paper presents the evaluation of the current PCPT interpretation methods for their capability to reasonably estimate the vertical coefficient of consolidation (cv) of cohesive soils utilizing the piezocone dissipation tests. The PCPT methods included in this evaluation are: Teh and Houlsby (1), Levadoux and Baligh (2), Robertson and Campanella (3), Teh (4), Senneset et al. (5) (two methods), and Jones and Rust (6). To achieve this goal, six sites in Louisiana were selected for this study. In each site, in-situ PCPT tests were performed and soundings of cone tip resistance (qc), sleeve friction (fs), and pore pressures at different locations (u1 and u2) were recorded. Piezocone dissipation tests were also conducted at different penetration depths. High quality shelby tube samples were collected close to the PCPT tests and used to carry out a comprehensive laboratory-testing program. The vertical coefficient of consolidation (cv), predicted using the different interpretation methods, were compared with the reference values determined from the oedometer laboratory tests. The results of this research study showed that the Teh and Houlsby (1) and Teh (4) methods can estimate cv better than the other prediction methods.